Flixger



WILLIAM F. DOERFLINGER, 0E HALESITE, NEW YORK.

LACQ'U'ER FOR AIRPLANE FRICS.

No Drawing.

To all whom it may concern:

Be it known that 1, WILLIAM F. Donn- FLINGER, a citizen of the United States, and

"a resident of Halesite, in the county of Suffolk and State of New York, have invented certain new and useful Improvements in Lacquers for Airplane Fabrics, of which the following is a specification.

This invention relates to improvements in lacquers for the textile fabrics used in the construction of airplanes, commonly known as wing or aeroplane dope. Such lacquers consist ordinarily of solutions of film forming colloids, such as, for instance, cellulose nitrate or acetate, dissolved in a suitable volatile solvent; to which may have been added various additional agents to soften, preserve or modify the film left on evaporation when the lacquer is applied to the textile fabric used in airplane construction (generally linen, cotton or silk cloth). The purpose of these lacquers is to shrink the fabric on to the frame work to a considerable degree of tautness and provide the planes with a smooth, waterproof, impervious coating. The object of this invention is to render' the film left on evaporation relatively non-inflammable, and is particularly desirable for lacquers in which the film forming element is cellulose nitrate, which is well adapted for the urposes of such lacquers, except that it is hlghly inflammable. It is of great importance that this result be achieved without unduly increasing the weight of the coating necessary to give the fabric suitable smoothness and tautness; and without rendering it brittle or increasing the tendency to deteriorate, crack, peel ofi' or weaken the fabric under the conditions'of use. It is desirable that the fire resistant lacquer be of a homogeneous nature, and that the fireproofing substance be notliable to settle out of the lacquer before it is applied or be unevenly distributed through it. q

I have found that the best results are A achieved in the preparation of fire resistant ing effect can be thus achieved with the Specification of Letters Patent.

' Application Med December 22, 1917. Serial 110108510.

weakened if suflicient of the agent is used to get the necessary fire proofing action; and the lacquer film is apt to become brittle and deteriorate on exposure.

The composition of my lacquer may, of course, be greatly varied without departing from the spirit of my invention. As a specific example to produoea fireproof lacquer from nitrocellulose according to my invention, I proceed as follows:

I dissolve 42 pounds of pyroxylin which will form a solution of medium viscosity (medium flow soluble cotton), 42 pounds of boracic acid, 38 pounds of triphenyl phosphate, and 14 ounces of urea in 50 gallons of methyl acetone (a commercial mixture of acetone, methyl acetate and methyl alcohol) or acetone, 40 gallons of commercial ketones, preferably malnly methyl-ethyl-ketone, boiling between about 80 C. and 120 C. and preferably about 7 5% boiling below 100 (l, and 10 gallons of benzole, producing a little over 100 gallons of lacquer. The lacquer thus produced is a clean transparent entirely homogeneous solution, which on evaporation in the ordinary conditions of use leaves the fabric, which may be untreated linen, relatively non-inflammable, so that ifgasolene be splashed on the dry coated fab- .ric and ignited the resulting'flame will not section of the film.

For each particular film forming colloid appropriate solvent must be used. The triphenyl phosphate is an example of a low 'melting point or liquid fire proofing agent,

but equivalent substances, such as tricresyl phosphate, suitable siliclc acid esters or highly chlorinated organic compounds may be used. Boracic acid is an example of a high melting point fire proofing agent, equivalent substances may. be substituted preferably soluble in the solvent, but this is not absolutely necessary. The functions of the urea in the specific example is mainly as a preservative or stabilizer, although it is also a high melting point fireproofing I increasing the proportion agent, although relatively inefficient.

The amount of fireproofing agent should be preferably as low as possible, and yet give the desired fireproofing efiect; and may be much lower for some film forming colloids than for others. By increasing the proportion of the higher melting point fire --proofing agent, the stretching effect of the lacquer is enhanced; While in general, by

of the low melting point fireproofing agent, the film is rendered more pliable and less liable to become brittle. With a very volatile solvent more of loW melting p'ointfire proofing agent may be used, than with a less volatile solvent; and still get the "necessary stretching efi'ect.

What I claim is:

1. A lacquer comprising a film forming colloid; a substantially non-volatile, low melting point fireproofing agents'oluble in the solvent, a high melting point fireproofing agent, and a volatile-solvent of thefilm forming colloid. 2. A homogeneous solution of a film forming colloid, a 10W melting point fire proofing agent, and a high melting point fireproofing agent in a volatile solvent.

3. A lacquer comprising a cellulose ester; a substantially non-volatile, low melting point fire proofing agent soluble in the solvent, a high melting point fireproofing agent, and a volatile solvent of the film forming colloid.

4. A lacquer comprising pyroxylin; a substantially non-volatile, low melting point fire proofing agent soluble in the solvent, a high melting fire proofing agent, and a volatile solvent of the film forming colloid.

5. A homogeneous solution of a cellulose 40 ester, a low melting point fire proofing agent, and a high melting point fire proofing agent in a volatile solvent.

6. A homogeneous solution of pyroxylin, a low melting point fire proofing agent, and a high melting point fire proofing agent in a volatile solvent.

7. A lacquer for aeroplane fabric, which will stretch the textile fabric to which it is applied, and render the coated fabric substantially non inflammable; comprising a clear solution of pyroxylin, a'volatile solvent of pyroxylin, a dissolved fire-proofing agent of low melting point, and a fire-proofing agent of high melting point.

8. A lacquer for aeroplane fabric consisting of a solution ofpyroxylin, boracic acid and triphenyl phosphate in a highly volatile solvent substantially as described.

WILLIAM F. DOERFLINGER. 

